Figure 4.
Association of variants in the HLA region with anti‐SSA/SSB–negative and anti‐SSA/SSB–positive patients. A, Association of variants in HLA region in patients with SLE (n = 544), primary SS (n = 241), or myositis (n = 247) who were negative for autoantibodies against SSA/SSB, as compared to healthy controls (n = 1,251). B, Regional association plot of HLA variants in patients with SLE (n = 168) or primary SS (n = 368) who were positive for autoantibodies against both SSA and SSB, as compared to healthy controls (n = 1,251). Few myositis patients (n = 11) had autoantibodies to both SSA and SSB, and therefore the data for these patients were not plotted. HLA alleles for 6 genes (HLA–A, HLA–C, HLA–B, HLA–DRB1, HLA–DQB1, and HLA–DPB1) and variants in C4 present in >1% of individuals were included in the analysis. Groups were analyzed for associations using logistic regression with adjustment for sex and PC1–PC4. Dashed lines represent the Bonferroni‐corrected significance threshold (P = 1 × 10−5). Color figure can be viewed in the online issue, which is available at http://onlinelibrary.wiley.com/doi/10.1002/art.42122/abstract.